1. Field
The field relates to a secondary battery, and more particularly, to a secondary battery capable of preventing the separation of an active material and increasing the adhesive force between electrode plates and a separator.
2. Description of the Related Technology
As the miniaturization and weight reduction of portable electronic devices make rapid progress, many studies have been conducted to develop secondary batteries used as power sources of the portable electronic devices. Such a secondary battery may, for example, be a nickel-cadmium battery, a nickel-hydrogen battery, a nickel-zinc battery, a lithium secondary battery and the like.
The lithium secondary battery is rechargeable, compact and has high capacity, and thus is widely applied to high-tech electronic devices because of its high operating voltage and high energy density per unit weight.
Such a lithium secondary battery is manufactured by inserting an electrode assembly together with an electrolyte into a case and then sealing the top of the case. The electrode assembly includes a positive electrode plate and a negative electrode plate, on which an active material is coated, and a separator interposed therebetween.
However, in the lithium secondary battery, a swelling phenomenon is easily generated by a reaction which generates gas in the manufacturing process of the lithium secondary battery, particularly, the reaction may occur in the process of electrolyte injection or charge/discharge. As a result of the swelling, the alignment of the electrode assembly is twisted, a short defect may occur or a non-discharge region may be produced.
Further, in the manufacturing of the lithium secondary battery, it is easy to generate dust of an active material in the process of notching or cutting the positive and negative electrode plates, in the process of fusing electrode tabs, and the like. Therefore, the short defect may occur.